This invention relates generally to flight simulators for use in the evaluation of aircraft controls and displays, and for training aircraft pilots, and more particularly to the portion of the simulator which corresponds to the throttle lever or levers in an aircraft.
In a modern military jet fighter, the throttle assembly typically comprises three levers arranged side-by-side. Two of these levers are throttle levers, one for each of two engines. The third lever is a flap control. Each throttle lever is pivoted about a fixed point, and movable forward from a rearmost "idle" position to a full throttle "military" position. With the lever in the full throttle position, it can be moved laterally to the left through a distance of about 1/4 inch, and then pushed further forward to activate an afterburner. The requirement for lateral movement from the full throttle position prevents accidental activation of the afterburners.
Grips on the throttle levers typically also include switches to operate the speed brake, to control wing sweep, to select radar modes, and to control weapons, and other aircraft systems, including a microphone, external lights, and a multi-function display.
In a simulator, it is desirable to reproduce, as closely as possible, the feel of the aircraft throttle lever, i.e. the resistance of the lever to movement, its apparent mass, and the smoothness of its operation. It is also necessary to provide an output signal, representing throttle position, for delivery to a computer which controls the simulator and records pilot performance. The output signal is typically a DC signal varying in the range from -10 volts to +10 volts.
Reproduction of the feel of an aircraft throttle lever is made particularly difficult by the requirement for a lateral shift to engage the afterburner. The requirement for a lateral shift and the requirement for a fixed pivot point, also make it difficult to produce a reliable throttle position signal.